The purpose of this research was to determine the feasibility of using a sealed composite restoration to arrest caries without cavity preparation and without the removal of the carious lesion. The only mechanical manipultion of the tooth was to bevel the enamel around the opening of the natural cavity at the aperture of the carious lesion. The bevel is limited to enamel only and is placed with a bur or diamond point. This minimal tooth preparation usually does not require any anesthetic injection and conserves tooth structure. These conservative sealed composite restorations are being compared with conservative sealed amalgam restorations and with standard Class I amalgam restorations. A total of 123 patients have had a total of 156 paired study restorations placed during a 13 mo. Baseline period (Feb. 1982 - March 1983). Evaluations of the study restorations have been carried out at 6 and 12 mo. Since the Baselines extended over a 13 mo. period, the evalutions tend to overlap among individual patients. The on-going 2-year evalutions will be completed by March 28, 1985. The 3-year evalutions will be completed by March 28, 1986. The budget of the current grant will continue through July 31, 1985. At 18 mo., a total of 50 restorations in a small group of patients were evaluated. The restorations showed no changes or only minimal changes. Therefore, the P.I. decided that evaluations at 6 mo. intervals are superfluous, and will continue with annual evaluations. At 2 years, the study restorations are in the process of being evaluated. Although only 48 pairs of restorations (a total of 96 restorations) have been evaluated at 2 years so far, the study restorations look extremely encouraging. Favorable results at 3 years may establish that these conservative restorations represent a viable interim measure; if favorable results persist at 6 years, the profession may consider these restorations as definitive treatment. The Principal Investigator therefore requests funding for an additional 4 year period to continue evaluating these conservative restorations and comparing them to the traditional amalgam restorations.